Crane



, ings h on the post A, and the outer end of the I UNITED STATES PATENT OFFICE.

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SPECIFICATION forming part of Letters Patent No. 374,756, dated December 13, 1887. Application filed March 23, 1887. Serial N 0. 232,107. (No model.) I

To all whom it may concern:

Be it known that 1, WILLIAM H. RIDGWAY,

a citizen of the United States,residing iu Goatesville, Chester county, Pennsylvania, have invented certain Improvements in Cranes, of which the following is a specification. My invention relates to that class of cranes in which a vertically-movable jib is employed, the inner and outer ends of said jib being supported by means of ropes or chains passing over suitable pulleys and connected to a hoisting device on the post of the crane, the main object of my invention being to provide such a crane with simple and effective means for operating the jib by steam or hydraulic pressure.

In the accompanying drawings, Figure 1 is a slde view of a crane constructed in accordance with my invention; Fig. 2, an end view of the same, looking in the direction of the arrow, Fig. 1, but without the supplementary cylinder; Figs. 3, 4, and 5, enlarged views of parts of the structure, illustrating details; Fig. 6, a perspective diagram showing one of the features of my invention, and Figs. 7 to 10 views illustrating modifications of certain features of the invention.

A is the hollow post of the crane, which consists of opposite side bars, a a, secured at their upper ends to a head-block, b, and at their lower ends to a base-block, d, said head and base blocks being provided with suitable projecting pivot-pins, c, the lower of which is adapted to a bearing in a plate, 0', the upper pin being adapted to any convenient bearing so that the post of the crane is free to swing on a vertical axis. Secured to and projecting outwardly at an angle from said post A is the arm B of the crane, the outer, end of which is connected to the head-block b'by suitable stayrods, f, this arm being, like the post, composed of opposite side bars, so as to provide a central opening for the reception of the vertically-movable jib D of the crane. The inner end of the jib D is supported by a chain, 9, which passes around a pulley, 9', free to turn on a shaft, h, the latter being adapted to bearjib is supported by a chain, 2', which passes round a pulley, i, at the outer end of the arm B and is connected to a bar, j, to which are also connected the ends of two chains, k, the

latter passing round pulleys It, also free to turn on the shaft h. By this means a down ward pull upon the inner ends of the chains 9 and It will cause the vertical lifting of the jib D of the crane, said jib descending as the inner ends of the chains are permitted to rise.

Various means have heretofore been devised for operating supportingchains so as to effect the raising and lowering of the jib of a crane, one of the commonest plans being to connect to a suitable Windlass or winch on the post of the crane the inner ends of two chains, the opposite ends of which are connected, respectively, to the inner and outer ends of the jib, and another plan is to connect the chains to the rod of a piston adapted to a fixed cylinder carried by said post; but these plans are objectionable, because they necessitate the use of a heavy weight on the inner ends of the chains in order to counterbalance the weight of the jib.

I operate the jib by means of steam or hydraulic pressure; but I reverse the construction ordinarily adopted when such power is .used and employ a fixed piston, M, and piston-rod M, in combination with a movable cylinder, N, the upper end of which is connectedto the inner ends of the hoisting-chains of the jib. By this means the weight of the hoistingcylind'er itself is available as a counterpoise for the movable jib; hence the usual extra counterbalance-weights are dispensed with, and the structure is simplified and cheapened and otherwise improved by reason thereof.

When steam-pressure is used, I prefer to have it act through the medium of a volume of water or other liquid, a supplementary cylinder, P, being located adjacent to the post A of the crane and being provided with steam inlet and exhaust pipes at m, a liquid-conveyer pipe, n, and a valved drain-pipe, n, the cylinder 1? being, in the first instance, filled with water or other liquid, so that the admission of steam through the pipem into the upper. end of the cylinder P will drive the liquidtherefrom and through the pipe a, while on cutting off the flow of steam through said pipe m and exhausting the steam through the pipe m the liquid is drawn back through the pipe n and into the cylinder P.

Ihe base-block d of the crane-post carries a flanged collar, 11, secured to the lower end of IOO the hollow piston-rod M, said base-block having two passages,'s and t, the passage 8 being formed in the body of the block' and the passage t in the pivot.

The liquid-conveying pipe it passes through the base-plate and through the passage 1!, and said pipe is in communication with the passage 8 through a bent pipe, '0, provided with a suitable stuffing-box, 1), so that the swinging of the crane-post on its axis will not interfere with the free flow of the liquid to and from the hollow piston-rod, all of the joints being readily accessible for inspection and repairs.

A stop-block, w, on the post A serves as a rest for the inner end of the jib D when the latter is at the limit of its downward movement, and the downward movement of the outer end of the jib is simultaneously arrested by a stop-block, :0, which is carried; by the outer end of the arm Band serves as a seat for a bumper-block, m on, the chain 2'. I

In order to prevent jar when the j ib reaches the limit of its upward movement, a. dash-pot, w, secured to the flanged collar p, receives'the projecting stuffing-box w of theeylinder M as the latter descends, the stuffing-box fitting the dash-pot so snugly as to confine the air therein and form a cushion. The mouth; of the dashpot is flared, and the stuffing-box is taperedto insure the proper engagement of; theparts, and the-openings in the base of the dash-pot which receive the stems of the confining belts are larger than said stems, soastopermit anydesired lateral movement of thesaiddash-pot. (S e Fig. 3.)

In order to permit the ready leveling of the jib of the crane when said level has been disturbed by uneven wear or stretch of thechains or from other causes, screw-connections RB. are provided between the supporting-chains g and iand the inner and outer ends of the jib, although only one of these connectiousmay be used, if desired, and in order to permit th proper centering of the pulleys g k. in respect to the cylinder N the shaft h is adjustable in its bearings by means of setscrews h", as sh own in Fig. 5.

The piston M which I prefer touse is constructed in the manner shown in Fig, 4, the shell S of the piston being connected to the hollow hub S by means of arms T, so as to permit the free flow of fluid from the hollow piston-rod to the space beneath the piston,

the under side of the shellbeingprovided with i an angular flange, u, of flexible material, the outer lip of which is caused by, pressure to bear firmly against the inner side-of the cylinder N, in order to prevent leakage.

As afu rther precaution against leakage, thepiston is provided with packing, y, compressedby means of a. follower, W, which is acted upon by nuts u, adapted to stud-bolts u, projecting upward from the shell of the piston. My invention may be carried out, however, without the use of the hollow piston and piston-rod. For instance, in Fig. 7 I have shown a modified construction of crane in which the pistonrod is solid, the connection between the cylinders N and I being effected by means of a flexible tube, n.

In a structure of the character described it is important that the strain shall be evenly distributed upon the cylinder N irrespective T of the position oftheload upon the jib D. Otherwise lateral twisting or straining of the cylinder will result when the load is nearer one end of the jib than the other. For this reason I use the double equidistant chains is as a meansof connecting the outer chain, i, to the cylinder, so that the strain on said cylinder, due to weight at the outer end of the jib, is exerted at equal distances on each side of the center of the cylinder, while weight at the inner end of the jib exerts a direct central strain on the cylinder, owing to the central connection of the chain g. By this means not only is unevenly distributed weight on the jib. prevented from laterally straining or swaying the cylinder, but such additional stability is imparted thereto as to correct any such tendency which might arise from the sudden swinging of the crane. This arrangement of chains isalso. available in those cranes in which the cylinder is fixed and the piston-rod movable, and my claim on this feature of my invention is intended to cover the latter construction as the-equivalent of that shown.

Various arrangements of chains may be adoptediwithin the scope of my invention. For instance,,in Fig. 8 I have shown chains k more widely separated than in Figs. 2 and 6,and in Fig. 9,;Ihave shown a double-chain connection for eachend of the jib. In all of these cases, however, the chains from each end of the jib are symmetrically disposed with reference to thecenter ot the hoisting devicethat is to say, whena single chain is used at one end of the jib it is connected directly to the center of the hoisting device, and when two chains are used. their connections are diametrically opposite and equidistant from the center of the hoisting device-so that precisely the same strain is exerted, on each side of the center of the latter.

The chains may be double throughout the entire length from the cylinder to the jib, if

desired, double pulleys in this case being provided at the outer end of the arm B. The con structionshown in Figs. 2 and 6 is, however, preferred. 7

Strain on the cylinder might be equalized. in a measure, when but two chains are used, by adapting said chains to sprocket-wheelssuchas shown in Fig. 10, for instance-these wheels being secured together, so as to be incapable of independent movement, either by securing them, to the shaft h and permitting the latter to turn or by securing the wheels together and permitting them to turn on the shaft. The use of sprocket-wheels is, however, objectionable; hence the multiplechain.

connection is preferred.

It will be evident that ropes may be usedin place of chains, if desired.

I claim as my invention- 1. The combination of the post of the crane, the vertically-movable jib and its suspendingchains, a cylinder connected to said chains, and a fixed rod, with piston contained in said I cylinder, whereby the cylinder serves to counterbalance or partially counterbalance the weight of the jib, all substantially as specified. 2. The combination of the post of the crane,

the vertically-movable j ib and its suspendingchains, the cylinder connected to said chains, a fixed piston contained in said cylinder, and a hollow piston-rod through which the motive fluid is introduced into the cylinder beneath the piston, all substantially as specified.

3. The combination of the post of the crane,

the vertically'movable jib, the actuating-cylinder, piston, and piston-rod forming a hoisting device, a chain or chains connecting one end of the jib to said hoisting device and exerting a central pull thereon, a chain or chains connecting the other end of the jib to the hoisting device, and means whereby said second chain or chains are also caused to exert a central pull upon the said hoisting device, all substantially as specified.

4. The combination of the post of the crane, the vertically-movable jib, the cylinder, piston, and piston-rod constituting the hoisting device, and suspension-chains connected to the opposite ends of the jib and having three or more points of connection with said hoisting device, the chains from each end of the jib being symmetrically disposed with reference to the center of the hoisting device and exerting the same strain on each side of said center, all substantially as specified.

5. The combination of the post of the crane, its projecting arm, and vertically-movable jib,

the suspension chains or ropes therefor, the actuating-cylinder, a stop-block on the post of the crane for supporting the inner end of the jib when it is down, a stop-block on the arm of the crane, and a block carried by the chain the upper side of the same, all substantially as specified.

7. The combination of the post of the crane, the vertically-movablejib, the actuating-cylinder, the suspensionchains, pulleys therefor,

a pulley-shaft, and means for adjusting the latter in a direction transversely to the cylinder, so as to properly center the pulleys in respect to the said cylinder, all snbstantiall y as specified.

8. The combination of the post of the crane, the vertically -movable jib, the suspensionchains, the actuating-cylinder, the fixed piston and its rod, and the dash-pot free to move laterally and adapted for the reception of a projection on the cylinder, all substantially as specified.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

WILLIAM H. RIDGWAY.

Witnesses:

G. RIDGWAY, A. O. RIDGWAY. 

